Re: Ctrl-C ignored after pasting a long text in an X terminal emulator
On Tue 24 Jan 2023 at 16:17:32 (+0100), Vincent Lefevre wrote:
> On 2023-01-22 23:27:27 -0600, David Wright wrote:
> > On Mon 23 Jan 2023 at 03:17:43 (+0100), Vincent Lefevre wrote:
> > > On 2023-01-22 11:33:57 +0100, Sven Joachim wrote:
> > > > This might be a limitation of Linux's pty(7) subsystem. The xterm
> > > > manpage mentions the following:
> > > >
> > > > ,----
> > > > | BUGS
> > > > | Large pastes do not work on some systems. This is not a bug in
> > > > | xterm; it is a bug in the pseudo terminal driver of those systems.
> > > > | Xterm feeds large pastes to the pty only as fast as the pty will
> > > > | accept data, but some pty drivers do not return enough information
> > > > | to know if the write has succeeded.
> > > > `----
> > > >
> > > > See also https://bugs.debian.org/273194 in xterm. Disclaimer: I do not
> > > > have any expertise in that area.
> > >
> > > Thanks. Since several terminals are affected (I've tested xterm,
> > > mlterm and GNOME Terminal), with exactly the same behavior, each
> > > after 4095 characters, this is probably this bug.
> >
> > I'm unconvinced. The bug was exhibited when the paste was into an
> > xterm running cat > /dev/null which should accept any amount of
> > input. I've catted 275KB to a real file, and got a perfect copy
> > every time.
>
> Indeed, this works fine with xterm and GNOME Terminal, even with
> "xterm; cat > foo" and the paste done before quitting the xterm
> (or whatever command that will not terminate immediately). But
> mlterm has some problems with that.
>
> I suppose that the terminal can detect when the pty will no longer
> accept additional characters. And the paste resumes as soon as
> input is read by "cat".
>
> With xterm, if I do the large paste with middle-click and type
> abc<Ctrl-C>def, then the end of the paste is missing, probably
> because the Ctrl-C occurred during the last write to the pty.
AFAIK whenever you interrupt a process with ^C, you're going to
have a problem with knowing exactly how much of the processing was
completed, and what sort of "tidying up/throwing away" was done.
The OP talked about posting "a long text". If you relax this to
include binary data, it wouldn't surprise me if surprises occur.
Cheers,
David.
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